/usr/lib/ghc-doc/hoogle/libghc-iso8601-time-doc.txt is in libghc-iso8601-time-doc 0.1.4-4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-iso8601-time-doc/html/iso8601-time.txt